Two-Dimensional Flying-Height Modulation Mapping at HDD Drive Level

A measurement system for flying-height modulation of magnetic heads is proposed, and two-dimensional (2-D) flying-height modulation mapping is demonstrated at the drive level. The measurement system is based on the triple harmonic method, which uses a readback signal from the read element of the magnetic head. This technique, which maintains a constant wavelength of the pattern for fly-height modulation measurement, was proposed to achieve 2-D flying-height modulation mapping. Moreover, the frequency response of the measurement system was calibrated, and measurement accuracy was improved